Alloy



Patented Apr. 30, 1935 Edward A. Gapillon, Attleborc, eric E. Carter, Maplewood, N.

1 and Fred- .i... assignors to Baker & Comp, Ina, Newark, N. 5., a corporation of New Jersey No Drawing. nd

1 1 application Serial No. 722,316. Divided and April 5. 1934,

application July 10, 1934, Seriai No. 734,506

This application is a division of our copending application Serial No. 722,316, and the invention relates in general to alloys and more particularly to an alloy to be used for the manufacture of watch cases, optical frames, jewelry, dental appliances and metal parts of dentures, electrical switch contacts and conductors and the like;

and the alloy may be used either alone or as a substitute for the gold alloys at present used in the manufacture of gold-filled or rolled gold plate articles.

One object of the invention is to provide an alloy containing a major portion of precious metals other than gold which shall be at least the equal of the gold alloys heretofore generally used in many properties and the superior of such gold alloys in other properties or characteristics for the purpose specified, and at the same time can be produced at less cost than the usual gold alloys.

Another object of the invention is to provide an alloy which shall be less subject to tarnish and more resistant to attack by nitric acid than gold alloys, and which shall be sufilciently soft to permit easy working without undue damage to tools and dies, and yet shall be hard enough to withstand wear and have some resiliency or springiness which is especially desirable in optical frames and jewelry.

Other objects and advantages of the invention will appear from the following description.

We have discovered that for the purpose described useful alloys can be produced by combining palladium, platinum and nickel when palladium constitutes at least thirty-five percent of the alloy. Palladium has a much lower specific gravity than gold, is less expensive and at the same time has better resistance to tarnishing and acid effect than the usual gold alloy, but palladium alone is too soft to withstand the wear incident to use in optical frames, jewelry and watch cases. The combining of the base metal nickel with the palladium, in part compensates this softness of the palladium and makes the alloy harder, although the alloy is much softer, than for example white gold. The addition of the nickel, also produces a certain degree of springiness in the alloy without material increase in cost which is desirable in optical frames and Jewelry. The alloy has a fine whitish color which in quality excells the quality of white gold.

The aforesaid alloy consisting of palladium and nickel, has a high degree of resistance to tarnish and acid attack, but the resistance is not com- 'plete. In many cases complete resistance to corrosion is highly desirable, and while wor to accomplish this result, we discovered that the addition to the other metals of a relatively small amount of platinum gives the unexpected effect of rendering the alloy practically completely resistant to tarnish and acid attack. Platinum is at the present time only slightly more costly than gold, and thus this remarkable effect of such a small amount of platinum, is obtained at only a slight increase in cost, which is important where it is desired to provide an alloy at about the same or lower cost than the usual gold alloys.

We have found that these metals can be combined in different proportions to produce satisfactory alloys. Good alloys may contain from thir yfive to seventy percent of palladium and platinum of which the major portion is palladium, the remainder of the alloy being nickel. The preferred alloy consists of about forty-five percent of palladium, about fifty percent of nickel and about five percent of platinum.

In all cases it is an important feature of the alloy that the small amount of platinum very remarkably and unexpectedly increases the resistance of the alloy to tarnish and acid attack, and the great significance of this feature is emphasized when the relatively low resistance of the other component metals of the alloy to tarnish and acid attack, is remembered.

The alloy is less subject to tarnish and attack by acids than the usual gold alloys. It has a lower specific gravity than gold and because of this and the lower cost of the metals, the alloy is less expensive than an alloy having a percentage of gold by weight equal to that of the percentage of the palladium and platinum in our alloy. The alloy is softer than white gold alloys and can be more easily worked, and yet is sumciently hard to withstand wear and has the springiness desirable in optical frames and jewelry. The quality of white color of the alloy is superior to that of white gold.

Having thus described our invention, what we claim is:

1. An alloy containing from thirty-five to seventy percent of palladium and platinum of which five to ten percent is platinum, the remainder of the alloy being nickel.

-2. An alloy consisting of about forty-five percent of palladium, about fifty percent of nickel and about five percent of platinum.

EDWARD A. CAPILLON. FEEDER-IO E. CARTER. 

